The endocrine role of the ultimobrancial glands and their relationship with the parathyroids to calcium homeostasis is examined in the frog, Rana pipiens. The serum and urinary response of calcium ions has been investigated in relationship to the movement of sodium. Removal of ultimobrancial blands (UBX) decreases the urinary excretion of sodium and increases urinary calcium; while parathyroidectomy (PTX) reduces both sodium and calcium excretion. Under some circumstances the hyponaturia is coincident with oliguria. Application of a mild sodium load does not reverse the decreased sodium excretion or oliguria in PTX or UBX-PTX frogs. A direct relationship exists between the amount of sodium and calcium excreted; which suggests that parathyroids may affect a sodium dependent calcium transport mechanism in kidney. Ultimobrancial glands decrease urinary calcium excretion, which also appears to be a sodium dependent mechanism; however, the responses are additive in UBX-PTX suggesting separate sodium mechanisms.